This invention relates to combination locks such as used on safes, doors of vaults, and the like. Many styles and forms of such locks are known in the art.
The present invention aims to provide a combination lock which is comparatively easy and inexpensive to manufacture, which is therefore suitable for use on comparatively inexpensive safes and strong boxes, and which is highly resistant to attempts to burglarize or break open the lock from the outside.
Other aims and objects of the invention are to provide such a lock so constructed as to minimize transfer of heat through the lock structure in case of a fire, and so constructed as to enable a large number of changes of the numerical combination needed to open the lock, without however going to the expense of providing movable and resetable parts on each lock wheel.
Another object of the invention is the provision of a combination lock having some or all of the above mentioned advantages, which is so constructed that the door to which the lock is applied may be closed and latched when the lock is in the locked position, without damaging or unduly straining any parts of the lock.
A further object is the provision of a lock design which can be adapted to any desired thickness of door or wall to which it is to be applied, and which can be mounted directly on the inner side of the door or wall itself, without having to be mounted in a separate box or compartment secured to the inner face of the door, as is necessary with many of the combination locks of the prior art.